JP2016170906A - Luminaire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a luminaire for emitting light under which a user hardly has a sense of discomfort and the user can easily read characters in use under a low color temperature environment, and light which relaxes the user.SOLUTION: In an illumination device, a first LED emits white light having as chromaticity deviation of Duv-1.6 to -12 at a correlation color temperature of 1563K to 4500K, and a second LED emits white light having a chromaticity deviation of Duv+10 to -1.6 at a correlation color temperature of 1563K to 4500K. The illumination light has a low correlation color temperature, white light which makes the paper surface look white is emitted from the first LED, and white light having a low awakening degree is emitted from the second LED. Therefore, it is possible to emit light under which a user hardly has a sense of discomfort and the user can easily read characters in use under a low color temperature environment, and light which relaxes the user.SELECTED DRAWING: Figure 6

Description

  The present invention relates to an illuminating device using an LED as a light source, and more particularly, to a technique for providing light that allows easy reading of characters and light that relaxes a user in a low color temperature environment with a correlated color temperature of 4500 K or less.

  Conventionally, the development of lighting devices has been advanced with the goal of faithfully reproducing the original color of the object to be illuminated. Specifically, the color appearance of various objects to be illuminated is closer to the appearance under standard light, and this can be objectively evaluated using the average color rendering index Ra.

  However, such an average color rendering index Ra may not necessarily be sufficient as an index for evaluating the readability of characters written on paper. Therefore, the chroma value calculated using The CIE 1997 Interim Color Appearance Model (Simple Version) as an index to quantitatively determine the whiteness of the paper based on the correlation between the readability of the characters and the whiteness of the paper. Are known. As an illuminating device that irradiates light whose chroma value is controlled, one that irradiates light having a correlated color temperature of 5400K to 7000K is known (for example, see Patent Document 1).

JP 2014-75186 A

  However, when the lighting device as described above is used as task lighting in a low color temperature environment, there is a large difference in the correlated color temperature between the task lighting light and the ambient (environmental) lighting light. May have a sense of incongruity. Moreover, although the light irradiated from such an illuminating device improves the readability of characters, for example, it does not give a relaxing feeling that invites the user to a comfortable sleep in reading before sleeping. .

  The present invention solves the above-described problem, and when used in a low color temperature environment, the user is unlikely to have a sense of incongruity, and can illuminate light that makes it easy to read characters and light that relaxes the user. An object is to provide an apparatus.

  The illumination device of the present invention includes a first LED that emits white light, and a second LED that emits white light having a correlated color temperature lower than that of the white light from the first LED and having a high chromaticity deviation Duv. And a controller that changes a light output ratio between the first LED and the second LED, and the first LED has a correlated color temperature of 1563K to 4500K and a chromaticity deviation Duv-1.6. The second LED emits white light having a chromaticity deviation Duv + 10 to −1.6 at a correlated color temperature of 1563K to 4500K.

  According to the present invention, the illumination light has a low correlated color temperature, and the first LED emits white light that makes the paper look white, and the second LED emits white light with a low arousal level. Therefore, when used in a low color temperature environment, it is possible to irradiate light that makes it difficult for the user to feel uncomfortable and that makes it easy to read characters and light that relaxes the user.

The perspective view which shows the bedroom in which the illuminating device which concerns on one Embodiment of this invention was installed. (A) is a top view of the light source part which comprises the said illuminating device, (b) is the II sectional view taken on the line of (a). The figure which shows the relationship between Duv under the task illumination light of various correlation color temperature, and the color of a paper surface. The figure which shows the relationship between Duv under the task illumination light of various correlation color temperature, the readability of a character, the whiteness of a paper surface, and the evaluation value of a preference. (A) thru | or (e) are the figures which put together the evaluation value of FIG. The xy chromaticity diagram showing the distribution of a character appearance white feeling improvement region and a relaxation region. The figure which shows the relationship between the wavelength of irradiated light, and a melatonin secretion suppression degree. (A) (b) is a figure which shows the test subject's average pupil diameter in various correlation color temperature and illumination intensity. The figure which shows the spectral sensitivity curve of endogenous photosensitivity retinal ganglion cell (ipRGC). FIG. 6 is a spectral distribution diagram of light having various correlated color temperatures. The figure which shows the relationship between ipRGC stimulation amount and an average pupil diameter. The figure which shows the relationship between correlation color temperature and ipRGC stimulation amount. The spectral distribution map of the light radiate | emitted from 1st LED, 2nd LED, etc. which comprise the said light source part. The xy chromaticity diagram showing a control example of the light output ratio between the first LED and the second LED. FIG. 3 is a spectral distribution diagram of light (three peak wavelengths) emitted from the first LED. The spectral distribution figure of the light (4 peak wavelength) radiate | emitted from said 1st LED.

  An illumination device according to an embodiment of the present invention will be described with reference to the drawings. As illustrated in FIG. 1, the lighting device 1 is configured as a bedside lamp placed beside a bed B in a bedroom R, for example, and includes a light source unit 2 that emits light.

  As shown in FIGS. 2A and 2B, the light source unit 2 includes a wiring board 3, a first LED 4 and a second LED 5 mounted on one surface of the wiring board 3, and the first LED 4 and the first LED 4. And a control unit 6 that controls a light output ratio with the two LEDs 5. The wiring board 3 is formed in a rectangular flat plate shape in the illustrated example, and one first LED 4 is mounted at the center thereof, and the second LED 5 is mounted at each of the four corners (peripheral edges). 1st LED4 and 2nd LED5 are arrange | positioned so that each optical axis may be orthogonal to the wiring board 3, and are comprised by white LED which radiate | emits white light with correlated color temperature 1563K-4500K.

  It was verified by experiment how the chromaticity deviation Duv can be controlled to make the characters written on the paper easier to read when the first LED 4 is irradiated with light having a low correlated color temperature of 1563K to 4500K. . The Duv referred to herein is described in the remarks of “5.4 Corresponding Color Temperature Applicable Range” in JIS Z8725: 1999 “Measurement Method of Light Source Distribution Temperature and Color Temperature / Correlated Color Temperature”. Yes, equivalent to 1000 times that described in ISO.

  In this experiment, the reference light and the test light were irradiated at an illuminance of 500 lx and a correlated color temperature of 3000K, 3500K, 4000K, 5000K, or 6200K, and the subject verified the readability of the characters under each condition. The reference light was Duv0 light at each correlated color temperature. The test light is Duv3, -3, -6, -9, -12, or -15 when the correlated color temperature is 4000K or lower, and Duv6, 3, -3 when the correlated color temperature is 5000K or higher. -6, -9 or -12 light. Such reference light and test light were generated by combining a xenon lamp with a liquid crystal filter and adjusting the optical characteristics of light emitted from the xenon lamp by the liquid crystal filter. The characters read by the subjects were 30 characters quoted from the reading vision chart (MNREAD-J), and were printed in the center of an average plain copy paper with a size of 7 points. Subjects were 12 men and women aged 24 to 51 years.

  In the experiment, after the subject had adapted to the reference light for 3 minutes, the text was read under the reference light for 5 seconds, and then the text was adapted to the test light for 40 seconds, and then the text was read under the test light for 5 seconds. It was done by evaluating the etc. After the initial evaluation, the character was acclimated to the reference light for 40 seconds, then the character was read under the reference light for 10 seconds, then the character was adapted to the test light for 40 seconds, and then the character was read under the test light for 5 seconds for evaluation. Repeated the operation to do. The evaluation consists of a color naming method (absolute evaluation method) that evaluates the appearance of the paper on which the letters are written under test light divided into “white” and “color”, and characters under reference light and under test light. It was performed by subjective evaluation consisting of a magnitude estimation method (relative evaluation method) that compares characters with each other.

  In the color naming method, the appearance of the paper surface under the reference light and the test light is first asked by the subject to answer in a ratio such that the sum of “white” and “color” is 100, then the color In the case where the user feels the color, he / she was asked to select a hue from yellow to green or red purple to blue purple. At this time, when yellow to green was selected, the color value was positive, and when red to purple was selected, the color value was negative.

  As a result, as shown in FIG. 3, it was found that when the correlated color temperature of the reference light and the test light is 3000 K, the color becomes zero when Duv-3 is set, and the subject feels the paper white. Further, it was found that when Duv is larger than -3, the yellowish green color increases, and conversely, when Duv is smaller than -3, the red-blue purple color increases. A similar change tendency was observed at other correlated color temperatures, but it was found that the lower the correlated color temperature, the greater the range of color change with respect to Duv, and the stronger the influence of Duv on whiteness. .

  Further, when the correlated color temperatures of the reference light and the test light are 3500K, 4000K, 5000K, and 6200K, it is found that the hue becomes zero when Duv-3, -1.6, 0, and 0 are set, respectively. Thus, it was found that Duv at which the tint is zero differs depending on the correlated color temperature.

  On the other hand, in the magnitude estimation method, the “readability” of the character under the test light is evaluated as a number greater than 100 if the readability under the reference light is 100, and the readability is lower than the reference light. If it was harder to read than under light, it was evaluated with a number smaller than 100. Similarly, the “whiteness” of the paper surface and the “preference” of the appearance of the paper surface were evaluated under the reference light and the test light.

  As a result, as shown in FIG. 4, when the correlated color temperature of the reference light and the test light is 3000 K, the evaluation value of the readability of the character is the highest when Duv-9 is set, and when it is Duv-6, The evaluation values of whiteness and preference were the highest. Similarly, for correlated color temperatures of 3500K, 4000K, 5000K, and 6200K, the optimum Duv was obtained for each of the readability of characters, the whiteness of the paper, and the preference.

  FIGS. 5A to 5E summarize the results obtained in FIG. As shown in FIG. 5A, when the correlated color temperature is 3000 K, the evaluation values of readability, whiteness, and preference are the highest in Duv-9, -6, and -6, respectively, as described above. (Indicated by circles). At this time, when the significant difference t test for the highest evaluation value was performed for each evaluation item, there was no significant difference in the range of Duv-12 to -3 in all the evaluation items (the range where there was no significant difference was indicated by dots). Show).

  Further, as shown in FIG. 5B, when the correlated color temperature is 3500K, all evaluation items are the highest in Duv-6, and the readability is Duv-15 to -3, and there is no significant difference. There was no significant difference between Duv-12 and -3 in terms of taste and preference. Further, as shown in FIG. 5C, when the correlated color temperature is 4000 K, all the evaluation items are the highest in Duv-3, and the readability is not significantly different in Duv-15 to -3. There was no significant difference in Duv-12 to 0, and preference was not significant in Duv-9 to -3. Further, as shown in FIG. 5D, when the correlated color temperature is 5000K, the readability and whiteness are the highest in Duv-6, and the preference is the highest in Duv-3. Was not significantly different in Duv-12 to 0, and whiteness and preference were not significant in Duv-9 to 0. Furthermore, as shown in FIG. 5 (e), when the correlated color temperature is 6200K, the readability is the highest in Duv-6, and the whiteness and the preference are the highest in Duv-3. Was not significantly different in Duv-12 to 0, and whiteness and preference were not significant in Duv-6 to 0.

  FIG. 6 superimposes and displays the evaluation results by the color naming method and the magnitude estimation method described above in the xy chromaticity diagram. For example, the case where the correlated color temperature of the reference light and the test light is 3000K will be described as an example. Points corresponding to Duv3, 0, −3, −6, −9, −12, −15 in the xy chromaticity diagram (circles) Are plotted). Among these, the point of Duv-3 is marked by a diamond mark indicating that the color of the paper surface is zero in the color naming method (see FIG. 3). On the other hand, from the magnitude estimation method (see FIG. 5 (a)), in the cases of Duv-3 and Duv-6, -9, and -12, “readability”, “whiteness”, and “preferred” It is known that there is no significant difference in all three evaluation items. In the range where there is no significant difference, Duv-12 which is the lowest Duv is marked with an inverted triangle mark. For other correlated color temperatures, diamond marks and inverted triangle marks are similarly marked.

  A line connecting diamond marks at each correlated color temperature was defined as a “minimum color curve” indicating that it is difficult to feel the color on the paper surface. The lowest color curve is represented by the approximate curve of the following formula 1, and according to this approximate curve, it was Duv-1.6 when the correlated color temperature was 1563K. In addition, a line connecting inverted triangle marks at each correlated color temperature was defined as an “allowable lower limit curve” indicating a lower limit at which the same effect as a point on the minimum color curve was obtained. The allowable lower limit value curve is represented by the approximate curve of the following formula 2, and according to this approximate curve, it was Duv-12 when the correlated color temperature was 1563K. A region sandwiched between these minimum color curve, allowable lower limit curve and correlated color temperature 4500K (indicated by diagonal lines) is easy to read characters in a low color temperature environment and to feel the whiteness of the paper surface. It was designated as “character appearance whiteness improvement region”. By controlling Duv so that it is plotted in such a character appearance whiteness enhancement region, the first LED 4 can emit white light that makes it easy to read the characters written on the paper.

(Equation 1)
y = −2.6186x ² + 2.5412x−0.2147... Formula 1
y = −3.1878x ² + 2.8976x−0.2836... Formula 2

  Next, when light with a low correlated color temperature of 1563K to 4500K was irradiated from the second LED 5, it was verified how Duv can be controlled to lower the arousal level and give the user a sense of relaxation. . The degree of arousal is closely related to melatonin, a hormone secreted from the pineal gland of the brain, and the secretion of melatonin causes a decrease in body temperature, the promotion of falling asleep, and the like, giving a person a sense of relaxation. As shown in FIG. 7, it is known that such secretion of melatonin is strongly suppressed by light having a wavelength of 464 nm. Therefore, it is considered that by cutting the light in the vicinity of the wavelength of 464 nm, the arousal level can be lowered and the user can feel relaxed.

  Light near a wavelength of 464 nm corresponds to blue light having a high correlated color temperature. Therefore, by cutting light with a wavelength of around 464 nm as described above, the color temperature of the irradiated light is lowered and Duv is raised. That is, if it is desired to obtain light that gives the user a sense of relaxation, the correlated color temperature of the irradiated light may be lowered and Duv may be raised. Therefore, the Duv region higher than the lowest color curve shown in FIG. 6 is set as a “relaxation region” that gives the user a sense of relaxation. The upper limit Duv of the relaxation region is set to Duv + 10 (indicated by a thick alternate long and short dash line) in the illustrated example. By controlling Duv so that it is plotted in a relaxation region sandwiched between such a minimum color curve and a curve representing Duv + 10, the second LED 5 lowers the arousal level and makes the user feel relaxed. The white light to be given can be emitted.

  Next, an experiment was conducted to investigate the relationship between the correlated color temperature and illuminance and the pupil diameter change of the subject. The pupil diameter has the same function as the diaphragm of a camera, and the focused range is expanded by narrowing the pupil (the depth of field increases). In this experiment, a combination of a white LED that emits white light of Duv-3 at a correlated color temperature of 3000 K and a blue LED that emits blue light having a peak wavelength at 480 nm was used as a light source. The illuminance was set at five levels of 300 lx, 500 lx, 750 lx, 1000 lx and 1500 lx, and the correlated color temperature was set at five levels of 3000K, 3500K, 4000K, 5000K and 6200K.

  In the experiment, two subjects in their 20s and 40s put their jaws on the chin stand under illumination light with a predetermined illuminance and correlated color temperature, and stared at a black spot with a diameter of 4 mm at a viewing distance of 45 cm. The pupil diameter was measured with 3 trials. The pupil diameter was measured using a hat type of an eye mark recorder (EMR-9) manufactured by NAC Image Technology. First, the illuminance was set to 300 lx, and after adjusting for 3 minutes with light having a correlated color temperature of 3000 K, the pupil diameter was measured for 15 seconds. Subsequently, the operation of measuring the pupil diameter for 15 seconds after the adaptation for 1 minute was repeated in the order of the correlated color temperatures of 3500K, 4000K, 5000K, and 6200K. Thereafter, in the same manner as in the case of illuminance of 300 lx, the pupil diameter at each correlated color temperature was measured in the order of illuminance of 500 lx, 750 lx, 1000 lx, and 1500 lx.

8 (a) is a plot of the average pupil diameter against mired (10 ⁶ times the reciprocal of the correlated color temperature), Fig. 8 (b), the average pupil diameter against logarithm of the illuminance It is a plot. The average pupil diameter was calculated from the average value of the 5 to 10 second interval after filtering by the moving median value of 10 points before and after (total 21 points) excluding measurement errors such as blinking, with 0 seconds as the measurement start time. As a result, it was found that the average pupil diameter decreases as the correlated color temperature increases and the illuminance increases.

  Intrinsic photosensitive retinal ganglion cells (ipRGC) are known as photoreceptor cells involved in such adjustment of pupil diameter. ipRGC is the third photoreceptor cell after cone cells and rod cells. As shown in FIG. 9, it is known that ipRGC responds most efficiently to light with a wavelength of 493 nm.

  FIG. 10 shows spectral distribution curves of light having correlated color temperatures of 3000K, 4000K, and 6200K used in this experiment. The light having a correlated color temperature of 6200K contains a lot of light having a wavelength of 493 nm and gives a high ipRGC response. On the other hand, light with a correlated color temperature of 3000 K does not contain much of the same light and gives only a low ipRGC response. The integrated value of these spectral distribution curves and ipRGC responsiveness was calculated, and the amount of stimulation of ipRGC by the light of each correlated color temperature was determined. The ipRGC stimulation amount was normalized by setting the ipRGC stimulation amount by the light (illuminance 1000 lx) emitted from the standard light source D65 as 100.

  As shown in FIG. 11, when the average pupil diameter shown in FIG. 8 is plotted against the ipRGC stimulation amount calculated as described above, the average pupil diameter decreases as the ipRGC stimulation amount increases. I understood. That is, if ipRGC stimulation amount is increased and ipRGC is stimulated strongly, the average pupil diameter is reduced and the depth of field is increased, so that the characters written on the paper can be easily read.

  Next, the ipRGC stimulation amount at an illuminance of 1000 lx was calculated for the light emitted from the first LED 4, that is, the light that makes it easy to read the characters written on the paper. As a result, as shown in Table 1 below, light having a correlated color temperature of about 3000 K and a Duv of −2.8 to −15.3 gave an ipRGC stimulation amount of 57 to 59. Further, light having a correlated color temperature of approximately 3500 K and a Duv of −2.5 to −14.5 gave an ipRGC stimulation amount of 62 to 64. Furthermore, light having a correlated color temperature of about 4000 K and a Duv of −2.8 to −14.9 gave an ipRGC stimulation amount of 68 to 70.

  On the other hand, the ipRGC stimulation amount was also calculated for the light emitted from the second LED 5, that is, the light that lowers the arousal level and gives the user a sense of relaxation. As a result, as shown in Table 2 below, light having a correlated color temperature of about 3000 K and a Duv of 0.4 to 6.4 gave an ipRGC stimulation amount of 55 to 56. Further, light having a correlated color temperature of approximately 3500 K and a Duv of 0.9 to 7.8 gave an ipRGC stimulation amount of 60 to 61. Furthermore, light having a correlated color temperature of about 4000 K and a Duv of −0.2 to 3.1 gave 67 ipRGC stimulation amounts.

  Furthermore, the ipRGC stimulation amount of light (illuminance: 1000 lx) emitted from the standard light source D65 and various general light sources (general fluorescent lamp, general LED, and light bulb) was calculated. As shown in Table 3 below, the ipRGC stimulation amount of the light from the standard light source D65 (correlated color temperature 6506K) was set to 100 as a reference as described above. On the other hand, light from a general fluorescent lamp (correlated color temperature 3199K to 7204K) gives an ipRGC stimulation amount of 49 to 90, and the ipRGC stimulation amount becomes larger as the correlation color temperature becomes higher. The light from the general LED (correlated color temperature 2882K to 7201K) gave an ipRGC stimulation amount of 42 to 101, and the ipRGC stimulation amount increased as the correlation color temperature increased, as in the case of the general fluorescent lamp. The light from the bulb (correlated color temperature 2750K) gave only 48 ipRGC stimuli.

  FIG. 12 is a plot of the ipRGC stimulation amount calculated as described above against the correlated color temperature. White light (indicated by a diamond mark) emitted from the first LED 4 gave an ipRGC stimulation amount equal to or greater than the value calculated by the following Equation 3. On the other hand, white light (indicated by an asterisk) emitted from the second LED 5 gave an ipRGC stimulation amount less than the value calculated by Equation 3. The amount of ipRGC stimulation of white light emitted from the first LED 4 and the second LED 5 is the amount of ipRGC stimulation of a general LED, a general fluorescent lamp or a light bulb at a correlated color temperature of 4500 K or less (triangle mark, square mark, x angle, respectively). It was larger than Therefore, the white light emitted from the first LED 4 and the second LED 5 has an average pupil diameter smaller than that of light emitted from a general LED, a general fluorescent lamp, or a light bulb at a correlated color temperature of 4500 K or less. The depth of field can be increased to make characters easier to read.

(Equation 2)
ipRGC stimulation amount = 0.0117 × correlated color temperature [K] +20.9...

  FIG. 13 shows a spectrum example (two peak wavelengths) of white light emitted from each of the first LED 4 and the second LED 5. As shown in 4 below, the white light emitted from the first LED 4 is, for example, correlated color temperature 3446K, Duv-5.7, ipRGC stimulation amount 66, average color rendering index Ra89, biological action strength 0.54. give. Here, the biological action strength is the action strength of melatonin secretion suppression calculated using the action amount prediction model (DIN 5031-100) of the German Standards Association Standard. The higher the value, the more the melatonin secretion is suppressed. Is shown. On the other hand, the white light emitted from the second LED 5 gives, for example, the correlated color temperature 2882K, Duv3.4, the ipRGC stimulation amount 42, the average color rendering index Ra81, and the biological action intensity 0.31.

  Further, in FIG. 13 and Table 4 above, the third action is to emit a white light having a lower biological action intensity than the white light from the second LED 5, that is, a white light with a high relaxing effect that hardly suppresses the secretion of melatonin. LEDs are also described. Such 3rd LED gives correlation color temperature 2006K, Duv2.8, ipRGC stimulation amount 25, average color rendering evaluation number Ra84, and biological action intensity | strength 0.14, for example. The light bulb used as a reference example gives, for example, a correlated color temperature of 2750 K, Duv 0.0, an ipRGC stimulation amount of 48, an average color rendering index Ra100, and a biological action strength of 0.35.

  Next, taking a reading before going to bed as an example, how to control the lighting of the first LED 4, the second LED 5 and the third LED described in Table 4 above will be described. As shown in FIG. 14, at the start of reading, the first LED 4 is turned on 100% (indicated by an asterisk, hereinafter referred to as the first state) and emits white light that is easy to read characters suitable for reading. . In this first state, the user can comfortably read.

  Next, the control unit 6 gradually decreases the light output of the first LED 4 as the lighting time of the first LED 4 elapses, and at the same time, gradually increases the light output of the second LED 5 to make the second LED 5 100%. Let it be a lighted state (indicated by a diamond mark, hereinafter referred to as a second state). The transition from the first state to the second state occurs in a natural atmosphere that is hardly perceived by the user because the correlated color temperature and Duv of the irradiation light gradually change. In the second state, light that hardly suppresses melatonin secretion is emitted from the LED 5, so that melatonin is secreted in the user's body, causing a decrease in body temperature, promotion of falling asleep, and the like.

  Then, the state is gradually shifted from the second state to a state in which the third LED is turned on 100% (indicated by an inverted triangle, hereinafter referred to as a third state). In this third state, light with a lower biological action intensity than in the second state is irradiated, and the secretion of melatonin is strongly promoted. Thereby, the user is guided to a comfortable sleep.

  In this way, the transition from the first state to the third state via the second state makes a smooth transition from the lighting environment suitable for reading to the lighting environment suitable for sleep gradually. Can do. Note that the transition pattern is not limited to the above, and may be, for example, a pattern in which a transition is made directly from the first state to the third state without passing through the second state, or from the first state. The pattern which transfers to a 2nd state and does not transfer to a 3rd state may be sufficient.

  As described above, the first LED 4 emits white light having a correlated color temperature of 1563K to 4500K and Duv-1.6 to -12 to make the paper surface appear white. On the other hand, the second LED 5 wakes up with white light having a correlated color temperature lower and a higher Duv than the white light from the first LED 4, specifically, correlated color temperatures 1563K to 4500K, Duv + 10 to −1.6. A white light with a low degree is emitted. Therefore, according to the lighting device 1, it is possible to irradiate light that makes it difficult for the user to feel uncomfortable when used in a low color temperature environment, and light that makes the user relax, and light that makes the user relax.

  Note that the white light emitted from the first LED 4 is not limited to the one having two peak wavelengths as shown in FIG. 13, for example, one having three peak wavelengths or one having four peak wavelengths. It may be. Therefore, a simulation was performed using three levels of half widths 20, 30, and 40 nm as parameters within a peak wavelength range of 420 nm to 660 nm (10 nm increments), and a virtual emission spectrum (Gaussian distribution) having three peak wavelengths was obtained.

  As shown in FIG. 15, the virtual emission spectrum having such three peak wavelengths has peak wavelengths in, for example, wavelength ranges of 420 nm to 480 nm, 520 nm to 570 nm, and 600 nm to 660 nm. The light of Example 1 (shown by the solid line) has peak wavelengths at wavelengths of 420 nm, 520 nm, and 600 nm, respectively. The light of Example 2 (shown by broken lines) has peak wavelengths at wavelengths of 480 nm, 570 nm, and 660 nm, respectively.

  Further, in the same manner as described above, a virtual emission spectrum having four peak wavelengths was obtained by simulation. As shown in FIG. 16, the virtual emission spectrum having such four peak wavelengths has peak wavelengths in, for example, wavelength ranges of 420 nm to 450 nm, 460 nm to 540 nm, 530 nm to 580 nm, and 600 nm to 660 nm. The light of Example 3 (shown by a solid line) has peak wavelengths at wavelengths of 420 nm, 460 nm, 530 nm, and 600 nm, respectively. The light of Example 4 (shown by broken lines) has peak wavelengths at wavelengths of 450 nm, 540 nm, 550 nm, and 620 nm, respectively. The light of Example 5 (shown by a two-dot chain line) has peak wavelengths at wavelengths of 440 nm, 500 nm, 580 nm, and 660 nm, respectively.

  As shown in Table 5, the light of Examples 1 to 5 described above gives ipRGC stimulation amounts 73, 91, 73, 70, and 70, respectively. Here, light having a correlated color temperature of 5000 K from a general fluorescent lamp that is generally used as task illumination light gives an ipRGC stimulation amount of about 70, as shown in FIG. That is, the light of Examples 1 to 5 gives an ipRGC stimulation amount equal to or higher than that of the general task illumination light having a correlated color temperature of 5000K, despite the low correlated color temperature of 3000K to 4500K. Therefore, according to the lights of Examples 1 to 5, the depth of field is sufficiently increased even at a low correlated color temperature by giving a high ipRGC stimulation amount, which is equivalent to the general task illumination light having a correlated color temperature of 5000K or More than that, the characters can be made easier to read.

  In addition, the illuminating device according to the present invention is not limited to the above embodiment, and various modifications can be made. For example, the lighting device is not limited to a bedside lamp, and may be configured as a standlight that is used on a desk or the like. A plurality of the first LEDs and the second LEDs may be provided, and may be mixed and arranged on the wiring board. By arranging in this way, it is possible to easily mix the white light emitted from the first LED and the white light emitted from the second LED.

DESCRIPTION OF SYMBOLS 1 Lighting apparatus 3 Wiring board 4 1st LED
5 Second LED
6 Control unit

Claims (8)

A first LED that emits white light;
A second LED that emits white light having a lower correlated color temperature and a higher chromaticity deviation Duv than white light from the first LED;
A control unit that changes a light output ratio between the first LED and the second LED,
The first LED emits white light with a correlated color temperature of 1563K to 4500K and a chromaticity deviation of Duv-1.6 to -12,
The second LED emits white light having a chromaticity deviation Duv + 10 to −1.6 at a correlated color temperature of 1563K to 4500K. In the xy chromaticity diagram,
The white light emitted from the first LED is plotted in a region sandwiched between a curve represented by the following formula 1 and a curve represented by the following formula 2.
2. The illumination according to claim 1, wherein the white light emitted from the second LED is plotted in a region sandwiched between the curve represented by the formula 1 and a curve representing the chromaticity deviation Duv + 10. apparatus.
(Equation 1)
y = −2.6186x ² + 2.5412x−0.2147... Formula 1
y = −3.1878x ² + 2.8976x−0.2836... Formula 2 In a value normalized by light having an illuminance of 1000 lx emitted from a D65 light source,
The white light emitted from the first LED gives an intrinsic light-sensitive retinal ganglion cell (ipRGC) stimulation amount that is equal to or greater than the value calculated by Equation 3 below.
3. The lighting device according to claim 1, wherein the white light emitted from the second LED gives an ipRGC stimulation amount less than a value calculated by the following Equation 3.
ipRGC stimulation amount = 0.0117 × correlated color temperature [K] +20.9...   The lighting device according to any one of claims 1 to 3, wherein the control unit lowers the light output of the first LED as the lighting time of the first LED elapses.   5. The white light emitted from the first LED has a peak wavelength in a wavelength range of 420 nm to 480 nm, 520 nm to 570 nm, and 600 nm to 660 nm, respectively. The lighting device described.   5. The white light emitted from the first LED has peak wavelengths in wavelength ranges of 420 nm to 450 nm, 460 nm to 540 nm, 530 nm to 580 nm, and 600 nm to 660 nm, respectively. The lighting device according to claim 1. The first LED and the second LED are mounted on one surface of a wiring board,
2. The wiring board according to claim 1, wherein one of the first LEDs is mounted on a central portion of the wiring board, and a plurality of the second LEDs are mounted on a peripheral edge of the wiring board. The lighting device according to claim 6.   The said 1st LED and said 2nd LED are provided with two or more, respectively, and are mutually mixedly mounted in the one surface of the wiring board, The Claim 1 thru | or 6 characterized by the above-mentioned. Lighting equipment.